


A Helping Hand

by SonicaSpeed123



Category: Undertale (Video Game)
Genre: Alternate Universe - Underswap, Fontcest, M/M, Underswap Papyrus, Underswap Sans
Language: English
Status: In-Progress
Published: 2016-03-31
Updated: 2016-04-02
Packaged: 2018-05-30 06:25:20
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 1,011
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6412588
Author URL: https://archiveofourown.org/users/SonicaSpeed123/pseuds/SonicaSpeed123
Summary: <blockquote class="userstuff">
              <p>My first sin in writing and I can't come up with a title.<br/>Underswap Sans goes through his first heat and Underswap Papyrus dwells on his feelings...</p>
            </blockquote>





	1. Warm and Gross Feelings

**Author's Note:**

> Super duper huge thanks to my fellow sinners from the chat room! You know who you are! Thank you so much for your support and interest!!!

Sans woke with a strange warm feeling in his bones. Rubbing the sleep from his eyesockets, he threw the blankets off his body. It wasn’t usually this warm in the house, was it? Maybe Papyrus turned up the thermostat?  
Sans sat up in his bed and jolted at the sudden shift he felt. The feeling became less pleasant and more… demanding of something. Like his very body was begging for something, but he had no idea what. Maybe getting up and moving would help a little…  
But the opposite proved to be true from the moment Sans lowered himself off his bed. That feeling migrated from his ribs, down his spine, and rested just above his pelvis. It caught him off guard when he heard his voice moan without him thinking. His hand snapped up to silence himself. What under earth was that?!  
He wasn’t sure why, but Sans prayed that Papyrus hadn’t heard. It would be embarrassing for his brother to hear him so… vulnerable. He was usually very in control over himself.  
Directing his thoughts back to the matter at hand, Sans sat back on his bed. Even the gentle friction from his pajama bottoms caused the feeling to spread and become more desperate, so Sans took his clothes off. He sighed a bit at the slightly cooler air, but was starting to sweat from the heat of the night.  
This was getting ridiculous.

On most nights, Papyrus rarely went to bed before 2 in the morning. Probably why he constantly napped. Sometimes he claimed that it was because of his nightmares (and a lot of the time it was), but many restless nights had been out of bad habit.  
Papyrus was no stranger to bad habits. Staying up too late, constantly napping, smoking, and the horrible, lustful daily fantasies about his brother. Those happened at night a lot, too, but recently, he’d find himself considering dropping everything to fuck his own brother. Disgusting. Bad habits, though, are hard to break. And as much as he hated to admit it, Papyrus didn’t really want to break this one. He knew he’d never lay a finger on his little bro, so he needed some way to expel all of the impure thoughts. At least he wasn’t doing anything to Sans in real life, right?  
Still, though, he felt pathetic when he called out for Sans in the night, long after he had gone to sleep.  
Tonight was different. It started out the same: say good night to Sans, go on Undernet and chat a bit, wait until Sans was asleep, then get some “thinking” out of the way. Once that was done, regret life choices, feel disgusting, and maybe try to actually sleep.  
He was just finishing chatting with an online friend when he heard sounds coming from Sans’s room. The house had thin walls, Papyrus had noticed, when Sans had brought up that he heard him calling for him one night. Even if someone was trying to keep quiet, if you listened closely, you could hear what someone was saying from another room. Papyrus always checked before he started since the morning Sans questioned him.  
The strange thing about hearing Sans tonight was… the noises he thought he heard. Papyrus could’ve sworn to Toriel that Sans was gasping and moaning, but there was no way… Sans hadn’t even had his first heat yet; he couldn’t possibly know how to touch himself, right? Unless he saw it on Undernet, maybe… Oh, god, what if he recognized Papyrus’s sounds? If he had somehow triggered this, he’d never forgive himself.  
He was dreaming, right? Just another dream that reflected the disgusting person that Papyrus was. He was just dreaming about his brother touching himself. It wouldn’t be entirely wrong to… join him then, right? It wasn’t real, there was no way this was real, so...


	2. here we gooooo

**Notes for the Chapter:**

> Ok this is like the shortest chapter ever i don't think i can even call it that but. I wrote it so take it if you want.

Papyrus stood outside Sans’s bedroom door, listening to Sans’s irregular breathing from the other side. God, he could feel his magic already. Sicko. He took in a deep breath and cracked the door a few inches.  
Truly and honestly, Sans was beautiful. Even if it was only in Papyrus’s imagination, he couldn’t deny just how perfect he looked, even in heat. Sans’s magic was a calm blue (which was, not by coincidence, Papyrus’s favorite color) that bathed the entire room in it’s light. Papyrus watched his brothers jerky movements, which seemed somewhat unsure and hesitant. He moaned every once in a while, but it clearly wasn’t getting him anywhere soon.  
Papyrus could help him finish.

This wasn’t working. No matter what he tried, no matter where he touched, it wasn’t enough to get the kind of reaction he heard Papyrus have. He’d heard Papyrus do stuff like this before. He thought it was gross back then, but now, he was begging to know what it felt like. He was begging to feel it too. He was about to give up and collapse when he noticed his door was cracked open.  
“Oh… thank God, Papy…” Sans’s own voice once again took him by surprise, but he didn’t care. “Could you… could you help me out here? God, please?”  
Sans saw Papyrus freeze up from behind the door, clearly surprised that Sans had noticed him. Sans was pretty sure he saw an orange flash in his eyes when he opened the door all the way. Papyrus stood almost threatening in the doorway, but that only made Sans’s pelvis ache more for some reason. Another unexpected groan.  
Papyrus grasped at his hoodie where his soul usually was. Did he upset him somehow? He hoped not… Sans needed help with this, and if Papyrus was mad, he might run off…  
But he didn’t. Papyrus moved his hands down to take off his hoodie. His ribcage and spine showed. They were built wide but the bones themselves were thin and smooth. Sans found himself staring and panting. He’d had feelings for Papyrus for a long time now, but he never imagined him like this…   
Sans liked it. His soul hummed in agreement.


End file.
